Tool retainer



May 8; 1928.

' E. W. STEVENS moor; RETAINER Filed July 18. 1925 Edward w $lfcv ns INVENTOI? BY yam ac. MM $1M; ATTORNEY Patented May 8, 1928.

UNITED STATES PATENT OFFICE.

EDWARD W. STEVENS, OI DETROIT, MICHIGAN, ASSIGNOR TO CHICAGO PNEUMATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

'rooL RETAINER.

Application filed July 18,

This invention relates to percussive machines, such for example as pneumatic hammers, and more particularly to retaining devices for the working tools of suchmachines. Among the objects of the invention are to provide a retainer which can be quickly applied and removed in. order to facilitate the interchange of working tools, to prevent a working tool from being discharged from a percussive machine if the latter is.inadvertently operated when the tool is not pressed 1 to the Work, and in general to simplify and to improve prior devices of this kind.

In order to illustrate the invention, concrete embodimentswthereof are shown in the accompanying drawings, in which Fig. 1 is a side elevational view of a'pneumatic hammer having the improved tool rewhich engages the'cylinder.

tainer mounted thereon; v

Fig. 2 is an enlarged sectional view of the end of thehammer shown in Fig. 1, taken substantially on the line 22 of Fig. 3;

Fig. 3 is a transverse sectional view taken on the line 33 of Fig. 2; 1

Fig.4 is a view similar toFig. 2 showing the means for mounting a difierent type of working tool; and

Fig. 5 is a transverse sectional view on th line 55 of Fig. 4. a

A typical use of the invention is illustrated in Fig. 1, wherein the retainer is mounted upon the end of the cylinder A of a pneumatic hammer for the purpose of retaining in operative position so as to be struck by the reciprocating piston B of the hammer, the working tool such as a rivet or button set C, which as indicated in Fig. 2 is provided with a shank 0 extending within the open end of the cylinder A and with an annular stop flange c.

The retainer comprises a sleeve 6 of substantial length, the inner or-rearward portion of which is adapted to extend over the outer end of the cylinder A and is provided upon its interior with a stop shoulder 7 The outer end of the retainer extends beyond the cylinder A and is provided at its extremity with an inwardly disposed annular flange 8 which cooperates with the flange c'- of the working tool C to prevent the latter from being dis charged from the percussive machine but per.- mitting limited axial movementof the work ingtool. A cushioning member such as a spring D may be, interposed between the 1923. Serial No. 652,368.

flanges 8 and c of the retainer and of the working tool.

The inner o-r rearward end of the retaining sleeve 6 is provided upon its exterior with spaced parallel annular rings or flanges 9 forming therebetween a groove 10. This groove is intersected by one or more slots 11 extending entirely through the sleeve and which in the form shown are two in number and diametrically opposed. Within the groove 10 is seated an open spring ring 12 having locking blocks 13 extending through the slots 11 in the sleeve to engage the cylinder A to securely hold the retainer thereon. While the locking blocks 13 may be shown in Figs. 2 and 4. The cylinder is provided upon its exterior with transverse cuts or slots 15 (Fig. 3) forming shoulders 16 (Fig. 2) behind which the blocks 13 snap when shoulder-7 of the sleeve, engages the cylinder.

In using the device with the working tool illustrated in Figs. 1 to 3, the spring D is first slipped over the outer end of the rivet set C and the latter is then inserted endwise into the retainer 6 with the-shank c extending rearwardly. The assembled tool and retainer are then forced over the end of the hammer cylinder A until the shoulder 7 of the retainer engages the latter and the blocks 14 snap behind the shoulders 16. The ham-' mer is then ready for use. Whenit is desired to remove the retainer as for the purpose of changing Working tools, theretainer sleeve 6 is gripped and rotated eitherto the left or right sufliciently to cam the locking blocks 13 out of the transverse cuts 15 in the cylinder whereupon the sleeve 6 may be pulled off the cylinder A without difiiculty.

Figs. 4 and 5 illustrate the manner of mounting upon the same or a similar ham mer, a different form of working tool E such as a chisel, illustrated in full lines in Fig. 4 ora punch indicated in broken line in the same figure. The sleeve retainer 5 remains unchanged but the manner of mountin the tool is slightly different. The shank eof t 'e workin tool E has secured thereon in any suitab e manner a bushing 20 adapted to fit and close the bore of the cylinder A and which is expanded at its outer end into a flange 21 which abuts the end of the cylinder. In the form shown one or more transversely disposed members such as pins 22 partly intersect the bore of the bushing and cooperate with flats 23 on the shank 0 whereby the working tool is held against rotary move ment but permitted limited axial movement relative to the bushing. As shown and by preference the bore of the bushing 20 is tapered inwardly, and the shank e of the working tool is similarly tapered so that when the tool is pressed to the work, thus disposing the parts in the position shown in Fig. 4, the working tool makes a tight fit with its guide bushing thereby promoting steadiness and accuracy of stroke when the tool isin operation. Relative axial movement of the bushing 20 within the projecting end of the retaining sleeve 6 may be permitted, and such movement of the bushing cushioned by suitable resilient members I such as the rubber buffers 24 utilized to pan tially fill the space between the retaining flange 8 of the sleeve 6 and flange 21 of the bushing. The operation of interchanging tools is vthe same as that described in relation to Figs. 1 t0 3.

From the above it will be apparent that the improved retainer herein disclosed in addition to facilitatingthe interchange of working tools acts as a safety device since it positively prevents a working tool from being inadvertently discharged, that pneumatic hammers now in use may be readily adapted to take this type of retainer by the simple expedient of cutting two transverse grooves near the open end of the cylinder,

and that the retainer is of few parts of rug-.

ged construction which can be manufactured and assembled at small cost.

While I have herein shown and described what I consider to be the preferred form of my invention, the same is readily susceptible of modifications and changes to adapt it for use with various types of percussive machines and of working tools therefor within the scope of the appended claims.

I claim:

1. The combination with the cylinder of a pneumatic 'hammer of a bushing fitting within the open end of said cylinder, a working'tool having its shank provided with a flat within said bushing, a pin in said bushing transversely intersecting the bore thereof and engaging said fiat on said tool shank to limit the axial movement of the tool relative to said bushing, and .a sleeve provided with locking means engaging'the cylinder for retaining said bushing in place, said sleeve also serving to keep said pin in said bushing.

2. The combination with the cylinder of a percussive tool of a bushing fitting within the open end of said cylinder and having a flange engaging the cylinder to form a stop, a working tool having its shank within said bushing and provided with a flat, said bushing flange having a transverse bore, a pin loosely fitting within the bore in said bushing co-operating with the flat in said tool shank to limit the axial movement of the tool relative to said bushing, anda retaining sleeve engageable with said hammer cylinder for maintaining said bushing in place, said sleeve also serving to keep said pin in said bushing bore.

Signed by me at Detroit, 12th day of July, 1923.

EDWARD W. STEVENS.

Michigan, this 

